int configure_output_filter(FilterGraph *fg, OutputFilter *ofilter, AVFilterInOut *out);
int ist_in_filtergraph(FilterGraph *fg, InputStream *ist);
FilterGraph *init_simple_filtergraph(InputStream *ist, OutputStream *ost);
int configure_output_filter(FilterGraph *fg, OutputFilter *ofilter, AVFilterInOut *out);
int ist_in_filtergraph(FilterGraph *fg, InputStream *ist);
FilterGraph *init_simple_filtergraph(InputStream *ist, OutputStream *ost);